The present invention relates to a centrifugal separator and a filter arrangement, for example for filtering combustion air for an internal combustion engine.
Centrifugal separators, also named cyclone filter, cyclone or cyclone separator, serve for separating solid or liquid particles contained in fluids. A fluid flowing into a centrifugal separator is guided such that centrifugal forces accelerate the particles to be separated from the fluid so that the particles can be collected within the separator. One configuration of a cyclone separator is a so-called axial or inline cyclone. An inline cyclone usually comprises a substantially straight tubular housing, called cyclone tube. The air to be cleaned flows through this cyclone tube. For generating the centrifugal forces, in most cases, guide blades are inserted at the inflow end of the cyclone tube, which guide blades generate a helical turbulent flow within the separator housing. Through these swirls, particles contained in the fluid are moved by the centripetal force radially outwards towards the cyclone tube so that the flow radially on the outside has a higher dust content than the flow radially on the inside. Downstream of the guide blade structure, an immersion tube usually extends into the cyclone tube, which immersion tube has a smaller diameter than the cyclone tube. Between the guide blade structure and the immersion tube, a spacing is usually provided in which a helical flow can form and thus the particles can be moved outwards. The portion of the flow radially on the outside with the higher particle content is discharged outside of the immersion tube, and the air cleaned in this manner flows axially through the immersion tube without changing the flow direction.
Axial or inline cyclones can be used, for example, as air filter for combustion air for internal combustion engines. In particular in the case of dust-laden environments in which in particular agricultural or construction machinery is used, cyclone filters or centrifugal separators have been proven to be suitable.
In order to increase the degree of separation of dirt particles from air or fluid, multi-stage filter arrangements have also been proposed in the past. Downstream of a cyclone prefiltration, another purifying filtering using conventional filter media can be carried out, for example. However, this is associated with increased manufacturing expenditure and additional limitations with regard to the installation situation of a corresponding filter arrangement. Thus, it is desirable to improve the filtering capacity of centrifugal separators, in particular when used as an air filter for internal combustion engines.